Investigation on the thermal and hydrodynamic performances of a micro-pin fin array heat sink for cooling a multi-chip printed circuit board

Abstract

Multi-chip printed circuit boards (PCBs) with integrated functionalities are widely used in large servers. This study investigates the thermal design of a PCB with nine different chips by using a micro-pin fin array heat sink. Four types of micro-pin fin arrays, namely, the square-pin fin array (SPFA), round-pin fin array (RPFA), truncated-pyramid-pin fin array (TPPFA), and truncated-conical-pin fin array (TCPFA), are considered, with the TPPFA providing the best thermal and hydrodynamic performances. The fabricated TPPFA heat sink was experimentally studied, achieving a maximum temperature of 63.3 °C, a temperature nonuniformity of 6.5 °C, and a pressure drop of 3.1 kPa at a total heat transfer rate of 540 W. Numerical simulations are conducted to examine the detailed temperature and flow distributions in the heat sink, exhibiting relatively uniform temperatures in the areas with micro-pin fin arrays and beneficial secondary flows in the downstream of the micro-pin fins. Further numerical simulations are performed to reveal the importance of the type of the coolant and the temperature dependence of the thermophysical properties, as well as the validity of the field synergy principle in analyzing the thermal performance of the heat sink considered in this work.